CRC CalculatorFile Checksum Calculator
Drop a file to get its CRC32, CRC-32C, CRC-64, Adler-32, MD5, SHA-1 and SHA-256 in a single pass. Paste the checksum you were given to confirm the file arrived intact.
Checksums
- CRC-32ZIP, gzip, PNG, SFV
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- CRC-32CCastagnoli — cloud storage, iSCSI
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- CRC-64/XZxz archives
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- CRC-64/NVMEAmazon S3 default checksum
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- Adler-32zlib streams
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- MD5legacy download checksums
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- SHA-1Git, older release pages
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- SHA-256current release checksums
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How to verify a downloaded file
- Find the checksum the publisher lists next to the download — a line such as
SHA256: 9f86d0…or a.sha256/.sfvfile. - Drop the downloaded file onto this page.
- Paste the published value into Expected checksum. Letter case, spaces and a
0xprefix are ignored. - A green row means the file is identical to the original. No match means it is not — download it again.
Which checksum is which
| Checksum | Length | Good for | Detects tampering |
|---|---|---|---|
| CRC32 | 8 hex digits | Catching transfer and storage errors; ZIP, SFV, PNG | No |
| CRC-32C | 8 hex digits | Cloud storage object checksums, filesystems | No |
| CRC-64 | 16 hex digits | Very large files, xz archives, Amazon S3 | No |
| MD5 | 32 hex digits | Legacy integrity checks | No — collisions are practical |
| SHA-1 | 40 hex digits | Git object IDs, older release pages | Weak — avoid for new uses |
| SHA-256 | 64 hex digits | Software releases, signatures, anything security-related | Yes |
The same checks from the command line
# Windows (PowerShell)
Get-FileHash .\file.iso -Algorithm SHA256
certutil -hashfile file.iso MD5
# macOS
shasum -a 256 file.iso
md5 file.iso
crc32 file.iso
# Linux
sha256sum file.iso
md5sum file.iso
python3 -c "import sys,zlib;print('%08x' % zlib.crc32(open(sys.argv[1],'rb').read()))" file.isoNote that the Unix cksum command prints a different CRC (CRC-32/POSIX with the file length mixed in), so its output will not equal the CRC32 shown here or in a ZIP listing.
To checksum text or hex bytes instead of a file, or to use a CRC with custom parameters, go to the CRC32 calculator.
Related tools
- Checksum calculator — the same idea for typed text and hex bytes, including simple sums, XOR and Fletcher-16.
- CRC64 calculator — the CRC-64/NVME and CRC-64/XZ variants in detail, with their parameters.
- CRC32 vs CRC32C — why two tools that both say "CRC32" can report different values for one file.
- What is CRC32? — what the checksum can and cannot tell you about a file.
Frequently asked questions
Is my file uploaded?
No. The file is read by your browser and the checksums are calculated on your own device. Nothing is sent to a server, so it is safe to use with private or confidential files.
Which checksum should I compare?
Use whichever one the publisher of the file provides. Software downloads normally list SHA-256. ZIP and SFV listings show CRC32. Older sites still list MD5 or SHA-1. Paste the published value into the "Expected checksum" box and the matching row is highlighted.
What does it mean if the checksum does not match?
The file on your disk is not byte-for-byte identical to the one the checksum was made from. Usually the download was interrupted or corrupted — download it again. If it still differs, the file may have been replaced or modified, and you should not run it.
Is a CRC32 file checksum enough to prove a file is genuine?
No. CRC32 reliably catches accidental damage, but it is easy to craft a different file with the same CRC32. To make sure a file has not been tampered with, compare a SHA-256 hash obtained from a source you trust.
Why is the CRC32 here different from the one my archive tool shows?
Check that you are comparing the same thing. 7-Zip and WinRAR show the CRC32 of each file inside an archive, not of the archive file itself. Also make sure the tool reports the standard CRC-32 and not CRC-32C.